Automatic pulse controlled servo control system

• US 4,236,106 A
• Filed: 10/16/1978
• Issued: 11/25/1980
• Est. Priority Date: 10/16/1978
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Gehman, John B., Davis, Doxie M.
• Primary Examiner(s): Dobeck, B.
• Application Number:
  US05/951,699
• Time in Patent Office: 771 Days
• Field of Search: 318/599, 318/650, 318/678, 318/286, 318/17
• US Class Current: 318/599
• CPC Class Codes: G05B 11/28 using pulse-height modulation; using pulse-width modulation

Abstract

A control system for the automatic adjustment of controlling elements. Theystem includes a pulse controlled servo follow-up circuit, a signal generating circuit, a sensing circuit, a system controller and a switching circuit. The system controller is either a special or small general purpose digital device which transmits a control signal to the switching circuit in response to the output of the sensing circuit. The switching circuit provides either of two variable time duration pulse control signals to the pulse-controlled follow-up circuit. One control signal will cause the follow-up circuit to provide a positive control and the other control signal will cause negative control. The amount of positive or negative control is determined by the time duration of the pulse. The signal generating device will be controlled by the output of the follow-up circuit and the sensing circuit will measure the condition of the signal generating circuit. The measured condition of the signal generating circuit, as measured by the sensing circuit, is transmitted to the system controller which will then provide another control signal to the switching circuit. The system has broad automatic servo control applications such as for machine controls and automatic circuit board testing.

Claims

1. A servo system comprising:

(a) a controller having a desired value reference signal and first and second output control signals;

(b) said first and second output control signals being operably connected to first and second switching elements;

(c) a drive element for operating in either a first direction or in a second direction;

(d) an element drive circuit responsive to said outputs of said first and second switching elements for controlling said drive element whereby said drive element is operated in said first direction when said first switch element is activated and operated in said second direction when said second switch element is activated;

(e) a controlled device having a control element and an output whereby said output indicates a measured value and is responsive to said controlled element;

(f) said drive element operably connected to said control element;

(g) said output being operably connected to the input of said controller;

(h) said first and second output control signals are variable in pulse length and the length of pulse determines the amount of movement of said drive element;

(i) said controller includes correction limit means and percent error means;

(j) means for comparing said percent error means to said corrective limit means;

whereby

(k) when said percent error is equal to or greater than said correction limit then said movement is a predetermined amount and when said percent error is less than said correction error than said movement is less than said predetermined movement and said controller provides said first output when said measured value is less than said desired value and said second output when said measured value is greater than said desired value for causing said measured value to about equal said desired value.